Process for the production of resistances



Feb. 24, 1942. w, BORN 2,273,941

PROCESS FOR THE PRODUCTION OF RESISTANCES Filed-Ju1y 26, 1938 2Sheets-Sheet 2 Patented Feb. 24, 1942 PROCESS FOR THE PRODUCTION OFRESISTANCES i Walter Dorn, Stuttgart, Germany, assignor to Robert BoschGelcllsclmft mit beschl'ankter Haftunz, Stuttgart, Germany Application 8Claims.

'I'he present invention relates to processes for the production ofmetal-paper resistances with predetermined resistance values.

It has already been proposed to make electric resistances frommetallised bands of insulating material, the metal coating being appliedon the paper preferably in the form of a meander. According to aparticularly advantageous process, the meander is produced byprintingthe paper with substances which give oil vapour in a vacuum, andthereafter vapourising-on a metal, i. e. applying metal in vapour form,the printed portions remaining free from metal. When using suchmetal-coated or metallised paper for resistances, it is desirable tohave the resistances available in prescribed lengths or cuttings ofdefinite resistance values, the limits of which cuttlngs are denoted byspecial marks orthe like, which may for example be done by omitting themeandering in the metal layer vaporised-on. It is also possible toseparate the several resistance cuttings from each other by runs ofnon-metallised paper. These non-metallised parts of the paper band can,given suitable length, also be used in place of the protecting coverwhich is otherwise specially wound on. i

It is furthermore of importance, when using such resistances ofmetallised paper, to provide a faultless metal connection with thecurrent supply. which entails certain difficulties in the case of metallayers of small thickness (in the resistances used metal layers of lessthan 1 ;z thickness are chiefly in question). When making resistancesfrom metallised bands of insulating material it is furthermore importantto increase the thickness of themetal layer at the points taking up thecurrent, which feature may suitably be automatically combined with themaking of the several' resistance cuttings.

According to the present invention theresistance of the metal layersproduced by vapouring a metal on to a band of insulating material isJuly ze, 1938, serial No. 221,387 Germany August 11, 1937 (ci. ati-89)connected metal layer.

measured continuously, and on attainment of the required value allowingfor the different constants of the manufacturing apparatus, a mark or adistinctive sign is produced on the resistance strip which may be donefor example by cessation of the meander impression and/or by shuttingof! the metal vapour Jet- It is also an essential feature of theinvention that, say by enlarging or widening the metal vapour ;let inthe direction of movement of the'band of insulating material, a thickermetal layer is applied on the paper support at the beginning and at theend of The invention is more particularly vdescribed with reference tothe accompanying drawings which show by way of example one form ofconstruction of resistance bandI in which runs of non-metallised paperare left between the single resistane cuttings. and in which Figurelshows a part of the support band with resistance of prescribed amountapplied thereon.

Figure 2 is a side view in diagram of the apparatus used for productionof the resistances. and

Figure 3 is a diagram of the wiiing arrangement.

In order to carry out the process, in place of the known form ofmeander, two meanders 2 and 3, having the width of the resistance strip,are applied on the paper support I, which may be coated on'both sides orlikewise only on the side receiving the metal coating with'a vamish orvamish-like insulating material, said meanders lying side by side andconsisting of one metallisation. The dividing line l between the twomeanders is, just like the meanders themselves produced by printing witha substance which in a vacuum and/or at high temperature gives offvapour, for example a fat (grease). If the printing roller is lifted ofifrom the paper during the vaporising, the meander stops, and at the sametime the dividing line l between the two meanders disappears. There isthen formed a'metal layer 5, which is unbroken and corresponds in itswidth to the lateralboundaries of the jet of vapour. and the length ofwhich is limited by swit'zhing off the jet of vapour.

In the manufacturing apparatus working in a vacuum (see Figure 2) thepaper support is drawn from a storage roll and is fed through thedriving rollers l and 8 or 9 and III respectively lying opposite eachother to the printing arrangement ||/|2 and the vaporising plant. Behindthe rollers 'l and 8 the printing roller ll with the back rolleropposite to it |2 is fitted. The printing roller can, in a manner knownin itself be constantly provided with the required quantity of theprinting agent by a storage roller not shown and which transmits theprinting agent. The printing roller ll is suspended on the lever 13which can pivot about the axis ll.

During the printing the printing roller ll is, by means of anelectromagnet, not shown, or another auxiliary device preferably ofelectric operation, pressed with the required pressure the resistancecutting, the meander, on disconagainst the paper support I running overthe netic device, so that it (the aperture) is reduced.

to a suitable narrow'slit. On cessation of the force acting on the slideII the aperture of the metal vaporising furnace is correspondinglywidened in the lengthwise direction of the paper to be metallised, andthe thickness of the metal layer vaporised-on correspondingly Increased.

After the band support I has, in its progressive movement in thedirection of the arrow, left the nozzle I6 of the metal vaporizingfumace I1, it reaches the contact rollers I 6, which press the band Iagainst the back roller II and make contact with it at the places of themeanders 2 and 3. The width of the contact rollers Il is so apportionedthat they about correspond to the width of the meanders 2 and 3 (seeFigure 3); overthe two rollers It current from the battery is fed to themeandering resistance passing by them, the amount of which current iscontinuously measured by the deflection of the needle 2| of themeasuring instrument 22. At the beginning of the measurement theresistance is relatively small, and the needle 2| of the measuringinstrument 22, undergoes a relatively large deflection through thecorrespondingly large amount of current. At that point of the scalewhich corresponds to the current corresponding to the 'desired amount ofthe resistance an adjustable contact 23 is fltted, which is inconnection with a circut 2| with the battery 25 and the relay 26. Thecircut 24 can be closed by the needle 2| as soon as the latter makcontact with the contact 23, in which case, by actuatlon of the relay 26the circuit 21 with the battery 26 is opened. In theecircuit 21 therelies the electro-magnet for pressing down the printing roller I I andalso the electromagnet which holds the slide IS in the position whichproduces a "normal narrow outlet slit in the vapour furnace I 1.

If when the paper strip I runs by, the desired resistance value isattained, or if the resistance meander is nterrupted by any derangementor by a defect of material, the needle 2| owing to takes place of theoutlet nozzle of the metal vapour furnace I1 the thickness of the metaldeposits is increased, and the meander thus increased finally, as soonas the parts of the paper which is no longer printed comes in front ofthe metal vapour nozzle is changed into a connected relatively thickmetal deposit.

of a second slide 2|. The consequence of this Is that the paper fromthat point onwards remains without metal coating.

By any suitable mechanism which may for example be actuated by thedriving rollers after running over a predetermined piece ofnon-metallised paper, the slide 23 is again pushed back at the beginningof the making of the next resistance cutting, so that out of the widenedaperture of the vapour furnace I1 a thick metal vapour jet is directedagainst the paper strip, and here again there is formed a connectedmetal deposit which oonstitutes the beginning of the new resistancecutting. By means of the needle 2| of the metering instrument 22 whichduring the time of non-vaporising, lies against the contact 23, thecircuit 2| is interrupted through the relay 26. The printing roller IIduring that time does not lie against the paper band I and the slide Ilreleases a wide outlet aperture Il of 'the metal vapour furnace I1.'I'herefore as soon as the slide 29 at the end of a non-vapouringperiod, releases the outlet of the metal vapour jet on to the-Paperstrip I, a relatively thick connected metal deposit is in the firstplace formed on the latter. As soon as this continuous metal depositwith relatively little resistance reaches the contact rollers Il, arelatively large amount of current fiows over it through the meteringin- As soon as this massive and thick metal coat- 4 ing comes betweenthe rollers IB, the resistance between these rollers becomes very small,as the current now takes the direct path through the thick metaldeposit. The measuring instrument 22 therefore indicates a high currentvalue, so

strument 22. The consequence is that the needle 2| leaves the contact23, and by de-energizing of the relay 26 the circut 21 is again closed.By a means which need not be specified here (for example a retardingrelay or the like) provision is made to ensure that, by the temporaryimpact of the needle 2| against the contact 30 the slide 23 is not atonce pushed again in front of the vapour nozzle of the metal vapourfurnace I1.

By olosing the circuit 21 the printing roller II is again pressedagainst the paper band I and produces the impression with grease or thelike required for the production of the meander form. Likewise, by thecircut 21, the slide IS is pushed in front of the aperture I6 of themetal vapour furnace I1, so that now only a slit of normal width, suchas is required for production of the normal meander, remains free. Byretarding measures of a kind known in themselves provision may be madein order that the narrowing of the outlet nozzle of the metal vapourfurnace by the slide IS shall only take' place after the first againprinted parts of the paper band have reached the metal vapour jet, sothat the originally greater thickness of the meandered parts of themetallising is gradualiy reduced to the normal thickness.

vA normal meander with normal thickness of the metal coating is nowproduced. The resistance of the part of the resistance meander producedfrom time to time is measured by the current of the 'battery 20 fed toit through the contact rollers IB, until, after the required resistancevalue has been attained, the needle 2I mak contact with the contact 23,and in this way the Operations are repeated in the manner describedabove.

The position of the contacts 23 and 30, the inertia of the relay 26 andalso that of the electromagnets which provide for the actuation of theprinting roller lever I3 and the slide IS can be so influenced by meansknown in themselves, that the desired operation(s) take place at themoments indicated from time to time. Needless to say, the two meandersrunning side by side can be used as one unit. In that case a resistancevalue is obtained which, with equal metal thickness and like .form ofmeander amounts to onefourth of the measured resistance. If therefore,it is desired to produce resistances with the highest possible value perunit of length, it will be better to make the resistance band with thetwo meanders of the two-fold desired width and to cut them apart alongthe separating line for the purpose of use.

It is no deviation from the essence of the invention if the dispositionof the several structural elements is modified as compared with theconstructional example illustrated and described, if the arrangementwhich serves for measuring the resistance cutting produced each time isa different one or likewise if the mechanical auxiliaries for thatpurpose, and also the mutual dependence and control is different fromthat which is the case in the constructional example described, providedonly that the inventive idea is the same as regards its principle.

With like meandering and like thickness of the metal deposit analteration of the resistance value can be effected by cutting apart adouble meander strip along the dividing line l. Moreover with likelength and like width a quadruplication of the resistance value can b,eobtained by removing the metal deposit which oon-.

nects them, at one end only of the double meander, and having a currentsupply to each meander end which thus arises.

I declare that what I claim is:

1. A process for the continuous production of resistances comprisingcoating a band of insulating material with metal to form contlnuouslythereon two adjacent spaced unform strips of metal of graduallyincreasing length, said strips being conductively connected at thebeginning end of each, constantly measuring the resistance of saidstrips during the production thereof by passing an electric currentthrough the whole length existing at any time on said band of bothstrips connected in series, and interrupting the production of saidmetal strips after a predetermined resistance value has been attained.

2. A process for the continuous production of resistance layers on bandsof insulation material having such a length that a large number ofresistances of the desired value can be produced thereon comprisingproducing two spaced adjacent uniform metal layers in the form ofmeanders of continuously increasing length on said band, said meandersbeing conductively connected at the beginning end of each, constantlymeasuring the resistance of said meanders during the production thereofby means of an electric current conducted through the whole lengthexisting at any time on said band of both meanders connected in series.and interrupting the production of the metallic meanders after attaininga predetermined resistance value.

3. A process for the continuous production of resistance layers on bandsof insulation material having such a length that a large number ofresistances of the desired value can be produced thereon comprisingproducing two spaced adjacent uniiorm metal layers in the form ofmeanders of continuously increasing length on said band, said meandersbeing conductively connected at the beginning end of each, constantlymeasuring the resistance of said meanders during the production thereofby means of an electric current conducted through the whole lengthexisting at any time on said band of both meanders connected in series,and producing a mark on said band when a predetermined resistance valuehas been attained.

4. A process for the continuous production of resistances comprisingapplying metal to a band of insulating material, moving said band pastthe metal-applying means to provide a substantially uniform conductivecoating of metal on said band, preventing application of metal atcertain points after an initial uniform application to provide twospaced adjacent metal strips conductively connected at their beginningends, constantly measuring the resistance of said strips duringtheproduction thereof by means of an electric current conducted through thewhole length existing at any time on' said band of both strips connectedin series, and interrupting the application of metal to said band aftera predetermined resistance value has been reached.

5. A process for the continuous production of resistances comprislngapplying metal to a band of insulating materialI moving said band pastthe metal-applying means to provide a substantially uniform conductivecoating of metal on said band, increasing the amount of metal applied atcertain periods without changing the rate of movement of said band toprovide thicker coatings of metal at certain points which merge with thethinner coatings at other points, preventing application of metal atcertain points after an initial uniform application to provide twospaced adjacent metal strips conductively connected at their beginningends, constantly measuring the resistance of said strips during theproduction thereof by means of anelectric current conducted through thewhole length existing at any time on said band of both strips connectedin series, and interrupting the application of metal to said band aftera predetermined resistance value has been reached.

6. A process for the continuous production of resistances comprisingapplying a vaporizable precipitation-preventing 'substance at spacedpoints along a band of insulating material and then metallising theuncoated portions of the material by thermal vaporization of metal invacuo while moving the band past the vaporizer to form two adjacentspaced metal layers in the form of meandersr on said band conductivelyconnected at their beginning ends, constantly measuring the resistanceof said meanders during the production thereof by means of an electriccurrent conducted through the whole length existing at any time on saidband of both meanders connected in series, and interrupting theapplication of metal to said band after a predetermined resistance valuehas been attained.

7. A process for the continuous production of resistances comprisingapplying a vaporizable precipitation-preventing substance at spacedpoints along a band of insulating material and then metallising theuncoated portions of the material by thermal vaporization of metal invacuo while moving the band past the vaporizer to form two adjacentspaced metal layers in the form of meanders on said band conductivelyconnected at their beginning ends, constantly measuring the resistanceof said meanders during the production thereof by means of an electriccurrent conducted through the whole length existing at any time on saidband of both meanders connected in series, and interrupting theapplication of the precipitation-preventing substance and of said metalto said band after a predetermined resistance value has been attained.

8. A process for the continuous production of resistances Acomrx'x'isinaappiyinz a vaporiaahle precipltation-preventinz aubstance at spacedpoints along a band of insulatin: material and then metallising theuncoated portions of the j material by thermal vaporization of metal invacuc while moving the band past the vaporiaer to form two adiacentepaced metal layers in the form of meanders on said band conductivelyconnected at their beginninl ends, inereasinz the 'amount of metalapplied at certain periods without changing the rate of movement of saidband w'determined resistance value has been attained.

WALTER DORN.

